Glass do not turn gaseous very easily. As expected, this makes them generally a better candidate for other means of laser engraving, most notably sandblasting or cutting using diamond tool. But when a laser hits glass or stone, something else interesting happens: it fractures. Pores in the surface expose natural grains and when they are heated very quickly, can separate a microscopic sized “chip” from the surface because the hot piece is expanding better relatively to its surroundings. So using Co2 lasers we can engrave on glass, and if the power, speed and focus are just right, excellent results can be achieved.